Conventionally, there have been provided IPS (In-Plane-Switching)-mode (transversal electric field type) liquid crystal displays as liquid crystal displays having a wide viewing angle characteristic. However, in the IPS-mode liquid crystal display, since a pixel electrode for modulating liquid crystal and a counter electrode are required to be located relatively close to-one another on one of a pair of substrates retaining the liquid crystal therebetween, a display light incident on a liquid crystal panel is blocked by both electrodes, thereby reducing a display light emanating from the liquid crystal panel. Consequently, luminance of a display screen is decreased.
An IPS-mode liquid crystal display for the purpose of addressing this problem has been disclosed, for example, in Japanese Laid-Open Patent Publication No. Hei 9-73101. FIG. 25 is a plan view schematically showing a pixel structure of the liquid crystal display. As shown in FIG. 25, in a pixel 402 of the liquid crystal display 401 in a plan view, a comb-teeth shaped pixel electrode 403 and a counter electrode 404 are disposed so as to oppose to one another, and at least one of the pixel electrode 403 and the counter electrode 404 is constituted by a transparent electric conductor, thereby reducing the amount of display light to be blocked by the electrodes 403, 404. Consequently, luminance of a display screen is increased correspondingly.
However, there is a problem in the liquid crystal display 401 as described below. FIGS. 26a and 26b are views schematically showing an operation of the liquid crystal display 401, wherein FIG. 26a is a sectional view showing an electric field and an alignment of liquid crystal molecules in a pixel, and FIG. 26a is a sectional view showing a transmittance distribution in the pixel. In these figures, constitutions of array substrates are simplified for the sake of illustration. In addition, the pixel electrode 403 and counter electrode 404 are here constituted by transparent electric conductors. As shown in FIG. 26a, the pixel electrode 403 and counter electrode 404 are provided on the array substrate 411 so as to oppose to one another (juxtaposed to one another) on the plane in which the array substrate 411 is present. Therefore, when a voltage is applied across the pixel electrode 403 and the counter electrode 404, an electric field is formed such that both of the electrodes 403, 404 are connected by bow-shaped lines of electric force 406, and liquid crystal molecules 405 are aligned along the lines of electric force. However, in an central portion of each of the electrodes 403, 404, there is formed a boundary of the lines of electric force of opposite directions, where liquid crystal molecules are aligned vertically with respect to the array substrate 411 (hereinafter, simply referred to as vertically) and along the lines of electrical force extending toward a point at infinity, thereby forming a liquid crystal disclination area 301. That is, the pixel is divided by the pixel electrodes 403 and the counter electrodes 404 into a plurality of domains. As a result, as shown in FIG. 26b, transmittance 302 of the liquid crystal panel (transmittance in a state in which a voltage is applied in a normally black mode; hereinafter simply referred to as transmittance) becomes high in an area located between the electrodes 403, 404 of the liquid crystal where the liquid molecules 405 are aligned horizontally with respect to the array substrate (hereinafter, referred to as horizontally) because a modulation rate of the liquid crystal molecules 405 becomes large, transmittance 302 becomes low in the disclination area 301 where the liquid molecules 405 are aligned vertically because a modulation rate of the liquid crystal molecules 405 becomes small, and transmittance 302 becomes medium in an area located above an portion other than the central portion of each of the electrodes 403, 404 where the liquid molecules 405 are aligned obliquely because a modulation rate of the liquid crystal molecules 405 becomes medium. The area 303 where the transmittance 302 is high, the area 304 where the transmittance 302 is medium, and the disclination area 301 respectively become a high contrast area, medium contrast area, and low contrast area. As described in the foregoing, since a display area includes the low contrast area 301, an average contrast of the display screen of the liquid crystal display 401 is reduced.